Motor fuel composition

ABSTRACT

MOTOR FUEL COMPOSITION COMPRISING A MIXTURE OF HYDROCARBONS IN THE GASOLINE BOILING RANGE CONTAINING A DETERGENT AMOUNT OF A PARTIAL ESTER OF A POLYETHOXLATED NHYDROCARBYL-1,3-PROPAQNEDIAMINE HAVING THE FORMULA:   R-N(-(CH2)2-O-R&#39;&#39;)-(CH2)3-N(-(CH2)2-O-R&#39;&#39;)2   IN WHICH R IS AN ALIPHATIC HYDROCARBON RADICAL HAVING FROM ABOUT 8 TO 20 CARBON ATOMS AND R&#39;&#39; IS HYDROGEN OR AN ACYL RADICAL DERIVED FROM A FATTY ACID HAVING FROM ABOUT 8 TO 20 CARBONS, AT LEAST ONE BUT NOT MORE THAN TWO OF SAID R&#39;&#39; SUBSTITUENTS BEING AN ACYL RADICAL.

United States Patent I Int. Cl. c101 1/22 US. CI. 44-62 v 15 ClaimsABSTRACT THE DISCLOSURE Motor fuel composition comprising a mixture ofhydrocarbons in the gasoline boiling range containing a detergent amountof a partial ester 'of a polyethoxylated N-hydrocarbyl-l,S-propanediamine having the formula:

in which R is an aliphatic hydrocarbon radical having from about 8 to 20carbon atoms and R is hydrogen or an acyl radical derived from a fattyacid having from about 8 to 20 carbons, at least one but not more thantwo of said R' substituents being an acyl radical.

BACKGROUND OF THE INVENTION Modern internal combustion engine design isundergoing important changes to meet new federal standards concerningengine exhaust gas emissions. A major change in engine design recentlyadopted is the feeding of blowby gases from the crankcase zone of theengine into the intake air supply to the carburetor rather than ventingthese gases to the'atmosphere as in the past. Further changes beingconsidered involve the recycling of a part of the exhaust to thecombustion zone of the engine in order to further reduce objectionableemissions. The recycled exhaust gases contain substantial amounts ofdepositforming substances which promote the formation of deposits in andaround the throttle plate area of the carburetor. These depositsrestrict the flow of air through the carburetor at idle and at lowspeeds so that an overrich fuel mixture results. This condition producesrough engine idling and stalling, and serves to increase the undesirableexhaust emissions which the engine design changes are intended toovercome.

Description of the prior art US. 2,902,354 discloses an anti-stallgasoline composition containing N-alkyl-1,3-propanediamine additives forgasoline as well as alkylene oxide derivatives of these diaminesexemplified by N tetradecylN,N',N'-tris-2-hydroxyethyl-1,1,3-propanediamine.

SUMMARY OF THE INVENTION A class of partial esters of polyethoxylatedN-hydrocarbyl-substituted 1,3-propanediamine compounds are provided ascarburetor detergents when employed in a liquid hydrocarbon fuel for aninternal combustion engine. These compounds, which are characterized byhaving a relatively long hydrocarbon radical attached to a nitrogenatom, as well as having one or two ester groups in the basic structure,appear to be unique in their detergency properties. Similar compounds inwhich all of the hydroxy groups have been esterified are essentiallyineffective as carburetor detergents. Polyethoxylated N 7hydrocarbon-substituted 1,3-propanediamine compounds, which areprecursors of the partial esters employed inithe present invention, aresusceptible to extraction by the tank water bottoms present in fueldistribution systems, ,making ;it difficult to maintainan efiectiveconcentration of the additive in the fuel composition. 7

The fuel composition of -the invention prevents or mitigates the problemof deposits lay down in the carbu- Patented Oct. 9, 1973 retor of aninternal combustion engine. When a gasoline of the invention is employedin a carburetor which already has a substantial build-up of depositsfrom prior operations, a rather severe test of the detergency propertyof a fuel composition, this gasoline is very effective for removingsubstantial amounts of the pre-formed deposits.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The partial ester of apolyethoxylated N-hydrocarbyl- 1,3-propanediamine of the invention isrepresented by the formula:

in which R is an aliphatic hydrocarbon radical having from 8 to 20carbon atoms and R' is hydrogen or an acyl radical derived from a fattyacid having from about 8 to 20 carbon atoms, at least one but not morethan two of said R' substituents being an acyl radical. A preferredembodiment of the invention is the monoester and diester in which leastone but not more than two of said R sub stituents represents an acrylradical having from about 16 to 18 carbon atoms and R is an aliphatichydrocarbon radical having from 16 to 18 carbon atoms.

There is criticality in the structure of an ester of a polyethoxylated Nhydrocarbyl-1,3-pr0panediamine in order to provide an effectivecarburetor detergent. The full esters, that is, the triesters ofpolyethoxylated N-hydrocarbyl-1,3-propanediamine, are essentiallyineffective as carburetor detergents when added to gasoline. In contrastto the triesters, the monoand diesters of these compounds exhibitunusual effectiveness for removing carburetor deposits.

The monoand diesters of the prescribed polyethoxyatedN-hydroxycarbyl-1,3-propanediamine are prepared by reacting 1 to 2 molesof a suitable fatty acid with approximately 1 mole of a polyethoxylatedN-hydrocarbyl1,3- propanediamine. This reaction is preferably conductedin an inert solvent. While the reaction temperature is not critical, itis preferred to conduct the esterification at a temperature ranging fromabout to 210 C. with the particularly preferred temperature of reactionbeing from to 200 C. The reaction is continued until the amount of thewater of esterification collected indicates that the reaction has beencompleted or substantially complete. The following examples illustratethe preparation of partial esters employed in the fuel composition ofthe invention.

EXAMPLE I 63.6 grams (0.12 mole) of N-tallow-N,N',N-tris-2-hydroxyethyl-1,3-propanediamine, 33.3 grams (0.12 mole) of a mixture ofaliphatic fatty acids consisting principally of stearic acid and 2.0grams of p-toluenesulfonic acid were combined in 300 milliliters ofxylene. The mixture was azeotrope distilled to a temperature of to 200C. while under a nitrogen atmosphere. The reaction mixture was refluxedat this temperature for 6 hours during which time the water ofesterification was collected. On completion of the reaction, the solventwas stripped from the reaction product. Theymonoesterified product,amounting to 95 grams, had a hydroxyl number of 125 as compared to thetheoretical of 141.

EXAMPLE II 31.8 grams (0.06 mole) ofN-tallow-N,N',N'-tris-2-hydroxyethyl-1,3-propanediamine, 33.3 grams(0.12 mole), of a fatty acid mixture consisting principally of stearicreaction, mixture was refluxed at this enipe rature for about 6 .hours.avhile tl; ie wat er. ,of .esterification swasocol-a v EXAMPLE III 42.4grams (0.08 mole) of N-tallow-N,N,N-tris-2'-hydroxyethyl-1,3-propanediamine, 66.7 grams (0.24 mole) of a fatty acidmixture consisting principally of stearic acid and"4.0 grams ofp-toluenesulfonic' acid were combined in 300 milliliters of xylene. Thereaction mixture, maintained under a nitrogen atmosphere, was azeotropedistilled to a pot temperature of 190 to 200 C. The reaction mixture wasrefiuxed at this temperature for about 6 hours while the water ofesterification was collected. On completion of the reactionv the solventwas stripped from the reaction product. The triesterified product,amounting to 104 grams, gave a hydroxyl number of 19 as compared to acalculated hydroxyl number of 0.

EXAMPLE IV 48.3 grams (0.091 mole) of N-tallow-N,N', -tris-2- EXAMPLE V532.0 grams (1.0 mole) of N-tallow-N,N',N-tris-2-hydroxyethyl-1,3-propanediamine, 574 grams (2.0 moles) of a fatty acidmixture consisting principally of linoleic and oleic acids were combinedin 350 milliliters of xylene. The reaction mixture was aseotropedistilled to a pot temperature of 180 C. and allowed to reflux at thistemperature for about 3 hours. While the water of esterification wascollected. After this time the reaction temperature was raised to 200 C.and the reaction mixture refiuxed at this temperature for about 1 hour.The diesterified product, amounting to 1068 grams, was obtained as a 88wt. percent solution in xylene. The xylene solution gave an OH No. of 71as compared to the theoretical of 47.

When tested in gasoline at a concentration of 10.0 ptb. (pounds perthousand barrels of gasoline) for carburetor detergency in the secondprocedure designated 11 and described hereinbelow, this diester wasessentially equivalent to the monoester of Example IV above.

Additional examples of partial esters which are eifective as detergentsin the gasoline compositions of the invention include the monoanddiesters of the following diamines:

A -tris,-2-hydroxyethyl-1,3-propane- '-tris-2-hydroxyethyl-1,3-propane---.nonanoie-, decanoic, =tetradecanoic, pentanoic; hexadecanoic andheptadecanoic.

The prescribed monoand diesters of N-C hydrocarbylN,N',N-2-hydroxyethyl-1,3-propanediamine are employed in the gasolinefuel .composition in a concentration to provide effective-carburetordetergent properties, In general, the esterstare employed .in 7 aconcentration ranging from about 0.0004 to 0.1 weight percent with apreferred concentration ranging from about 0100110004 and amostpreferred" concentration ranging from 0.002 to 0.005 weight percent.

Any gasoline suitable for aspark-i'gnited, internal combustion engine"can be used in the pracnceiar this invention. In general, the basefuelwill consist of a mixture of hydrocarbons in the gasoline boilingrange, i.e., boiling from about 75 to 450 Ff'The hydrocarbon componentscan consist of paraffinimnaphthenic, aromatic and olefinic hydrocarbons.This gasoline can be obtained naturally or it can be produced by thermalor catalytic cracking and/ or reforming of petroleum hydrocarbons. Thebase fuel will generally have a Research Octane Number above 85 and upto about 102 Withthe preferred range being from about 90 to 100. p 1

The prescribed partial esters .of N-hydrocarbyl trishydroxyethyl-1,3-propanediamine additive were tested for effectivenessin the carburetor detergency test. This test is run on Chevrolet V 8 engirie mounted on a test stand using a modified four-barrel C3.Ibl1IClO1-*The two secondary barrels of the carburetor are sealed and the feed toeach of the primary barrels-arranged so that the de-i tergent additivefuel can run inone barrel and the ref; erence fuel run in the other. Theprimary carburetor barrels were also modified to contain removablealuminum inserts in the throttle plate area so that the deposits formedon the inserts couldbe conveniently weighed.

Two procedures wereused to determine the effectiveness of additive fuelfor removing preformed deposits in the carburetor. In. the firstprocedure,--;des ignated I, the engine is run for a periodof time,usually 24 or 48 hours, using the base fuel as the feed to bothbarrelswith engineblow-by circulated to the air inlet of the carburetor. Theweight of the deposits onboth sleeves is determined-and recorded. Theengine is then cycled for '24 additional hours with base fuel beingfed-to one-barrel and the additive fuel to the other and no .blow-by to.the carburetor air irdet. The inserts are then removed-fromthe-carburetor and weighed to determine the difference between the peraformances of the additive and non-additive fuels for removing preformeddeposits. After the aluminum inserts have been cleaned, they arereplaced in the carburetor and the process repeated with the'fuelfeeds-intothecarburetor reversed in order to minimize difierences'infueldistribution and carburetor" construction. The results obrun fora-period' of time; usually' 24 to 48 hours, using" the base'fue'l as thefeed to both barrelswith engine blow-byeirculat'ed' to'the air inlet ofthe carburetor. The weight of the deposits-on both sleeves is determinedand recorded. The engine is then cycled'f'or 24 additional hours withbase fnelcontaining a recognized commercial additive ata'concerit'ra'tion of 50 ptb. being fed to one barrel and the additivefuel to the other. During the'cycle engine blow-by is circulated to theair inlet of the carburetor. The inserts are'then removed from" thecarburetor and weighed to determine thediiference between the performances 'of the additive and commercial detergent fuels for removingpreformed deposits. After the aluminum ins'erts have beencleaned,"=-they are replaced in the carburetor'arid' the processrepeated with the fuel feeds into the carburetor reversed in order tominimize differences in fuel distribution and carburetor construction.The results obtained in the two runs are averaged and the elfectivenessof the reference fuel and of the additive fuels for removing depositsexpressed in percents.

The base fuel employed in the following examples -was a premium gradegasoline having an octane number of about 99.2 and containing 3 cc. oftetraethyl lead per gallon. This gasoline consisted of about 25.5percent aromatic hydrocarbons, 95 percent olefinic hydrocarbons and 65percent parafiinic hydrocarbons and boiled in the range from about 90 F.to 370 F.

Fuel compositions of the invention were tested in the ChevroletCarburetor Detergent Test and the results set forth in Table I below.The percent effectiveness reported is the difference obtained bysubtracting the percent eifectiveness of the reference fuel from thepercent effectiveness of the additive fuel.

TABLE I.-CARBURETOR DETERGENCY TEST 1 Concentration in pounds perthousand barrels of gasoline.

The foregoing data, specifically Runs 1, 2, 3, 4, 5 and 7 illustrate thesurprising effectiveness of the prescribed partial esters as carburetordetergent in motor fuel compositions. In contrast, Run 6, wherein thefully esterified tristearate ester of N-tallow-N,N,N' tris 2hydroxyethyl-1,3-propanediamine was employed in the gasolinecomposition, was essentially ineffective as a carburetor detergent.

The fuels of the invention may contain any additive conventionallyemployed in gasoline. Tetraalkyl lead, antiknock additives, dyes,corrosion inhibitors, anti-oxidants and the like can be beneficiallyemployed without materially affecting the detergent additive of theinvention. Gasolines containing from about 0.01 to 0.20 volume percentof a polymer, copolymer or the corresponding hydrogenated polymer orcopolymer of a C to C unsaturated hydrocarbon having a molecular weightin the range of 500 to 3,500, preferably from 650 to 2600, as describedin US. 3,502,451, which disclosure is incorporated in this application,in combination with the detergent of the present invention areparticularly effective multifunctional fuels, compositions containingpolypropylene and polyisobutylene of 80 to 1100 molecular weight at fromabout 0.025 to 0.1 volume percent being preferred.

I claim:

1. A motor fuel composition comprising a mixture of hydrocarbons in thegasoline boiling range containing from about 0.0004 to 0.1 weightpercent of a partial ester of a polyethoxylatedN-hydrocarbyl-1,3-propanediamine having the formula:

in which R is an aliphatic hydrocarbon radical having from about 8 to 20carbon atoms and R is hydrogen or an acyl radical derived from a fattyacid having from 8 to 20 carbon atoms, at least one but not more thantwo of said R substituents being an acyl radical.

2. A motor fuel composition according to claim 1 in which the aliphatichydrocarbons radicals represented by R and R have from 14 to 20 carbonatoms.

3. A motor fuel composition according to claim 1 in which R consistspredominantly of C and C aliphatic hydrocarbon radicals.

4. A motor fuel composition according to claim 1 in which said partialester is essentially a mixture of monoand diesters.

5. A motor fuel composition according to claim 1 in which said partialester is a monostearate.

6. A motor fuel composition according to claim 1 in which said partialester is a distearate.

7. A motor fuel composition according to claim 1 in which said partialester is a monooleate.

8. A motor fuel composition according to claim 1 in which said partialester is a dioleate.

9. A motor fuel composition according to claim 1 containing from about0.001 to 0.04 weight percent of said partial ester.

10. A motor fuel composition according to claim 1 in which said partialester is a monolinoleate.

11. A motor fuel composition according to claim 1 in which said partialesters is a dilinoleate.

12. A motor fuel composition according to claim 1 containing from about0.002 to 0.005 weight percent of said partial ester.

13. A motor fuel composition of claim 1 which additionally contain fromabout 0.01 to 0.20 volume percent of (l) a polymer of a C to Cunsaturated hydrocarbon (2) a copolymer of a C to C unsaturatedhydrocarbon, or (3) the corresponding hydrogenated polymer or copolymer,said polymer or copolymer having a molecular weight in the range fromabout 500 to 3,500.

14. A motor fuel composition according to claim 1 containing from about0.025 to 0.1 volume percent of polypropylene having a molecular weightranging from about 800 to 1100.

15. A motor fuel composition according to claim 1 containing from about0.025 to 0.1 volume percent of polyisobutylene having a molecular weightranging from about 800 to 1100.

References Cited UNITED STATES PATENTS 3,502,451 3/1970 Moore et al.44-58 1,692,784 11/ 1928 Orelup et al. 44-66 3,374,174 3/1968 Le Suer44-71 2,854,323 9/1958 Shen et al. 44-71 2,902,354 9/ 1959 Giammaria44-72 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant ExaminerUS. Cl. X.R. 44-66, 71,

